Is that an accurate quote? If it is it's clearly just wrong - perhaps she was meaning to say there would be no E&C without that particular group...which is questionable, to say the least. However, my understanding of the speech as represented on this site is that she said that the local Latin American population are 'Londoners first...' not the first Londoners - fair enough.

I think it could be said about people groups from all areas of London. Clapham, for example, is heavily populated by Australians and one could argue that there would be no London without Australians or Asians, or Africans, or some European nations (Poland springs to mind). So effectively one is saying, "In order for London to be London, it has to celebrate tolerance and diversity."

London, as a geographical location, would actually still exist if nobody lived in it, but I guess she was trying to suggest that it's London's people that make it alive and keep it vibrant, and without our Latin American neighbours, London would be poorer.

but I guess she was trying to suggest that it's London's people that make it alive and keep it vibrant, and without our Latin American neighbours, London would be poorer.
I can't see what's contentious.

That's one interpretation, a viewpoint which I assume is yours, Homeletter - and if she had said that I doubt if there could be a serious challenge to her statement - but [it appears] she didn't state her viewpoint in those terms.